What are the components of the Loggregator system?
Metron - Forward logs to the Loggregator subsytem
Doppler - gather logs from Metron
Traffic Controller - handles client requests for logs
Firehose - a websocket endpoint that exposes app logs, container metrics and ER component metrics
Nozzles - consume the firehose output
How do you scale an application manually?
cf scale -m -i
What are the four levels of high-availability provided by PCF?
BOSH detects and recreates failed VMs
BOSH also detects and restarts failed processes
Application instances are automatically spread -- Across different Cells -- Across Cells in different Availability Zones
CF Converger detects if an application instance has failed and restarts it
What is the difference between scaling up and scaling out?
scale up (vertically) increases the disk space limit or memory limit of all instances of an application. It requires downtime as the container is recreated.
scale out (horizontally) increases the number of instances of an application by creating or destroying them. It requires no downtime.
pluralsight recap
What are some fundamental changes impacting application design and delivery?
Distributed computing
Ephemeral infrastructure
Immutable infrastructure
What is a modern methodology for delivering cloud based applications?
Twelve-factor app
How are logs handled in a Twelve-factor app?
As event streams
True or false, Garden is an interface with many implementations.
True, there's Linux and Windows and more on the way
Which component of the Elastic runtime exposes an API for users to manage applications?
Cloud controller
What are the four levels of high availability that keep your applications running?
Availability zones
BOSH managed processes
Failed VMs - any VM that BOSH deploys will be recreated if you enable resurrector
Self healing application instances handled by the brain within Diego
Where should you write your application logs?
To Standard Out and Standard Error
What are some of the different origin codes that were seen in the log?
cf logs
API for cloud controller
stage for stating
cell for running applications
What did you think about accessing the logs? How is that different from what you do today?
What is the difference between scaling out versus scaling up?
Scaling up requires down time to recreate the container Scaling horizontally requires no downtime
How do you recover failed application instances today? What happens if the underlying platform fails? How do you recover from that?
How could you tell if your application has been crashing?
Look at the logs, but probably the best place to go is cf events
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